python-matplotlib: update to 3.6.0

mingw-w64-python-matplotlib/001-fix-pointer-declaration.patch

@@ -0,0 +1,19 @@
+--- a/src/_tkagg.cpp
++++ b/src/_tkagg.cpp
+@@ -231,13 +231,13 @@
+ {
+     // Try to fill Tcl/Tk global vars with function pointers.  Return whether
+     // all of them have been filled.
+-    if (void* ptr = dlsym(lib, "Tcl_SetVar")) {
++    if (auto ptr = dlsym(lib, "Tcl_SetVar")) {
+         TCL_SETVAR = (Tcl_SetVar_t)ptr;
+     }
+-    if (void* ptr = dlsym(lib, "Tk_FindPhoto")) {
++    if (auto ptr = dlsym(lib, "Tk_FindPhoto")) {
+         TK_FIND_PHOTO = (Tk_FindPhoto_t)ptr;
+     }
+-    if (void* ptr = dlsym(lib, "Tk_PhotoPutBlock")) {
++    if (auto ptr = dlsym(lib, "Tk_PhotoPutBlock")) {
+         TK_PHOTO_PUT_BLOCK = (Tk_PhotoPutBlock_t)ptr;
+     }
+     return TCL_SETVAR && TK_FIND_PHOTO && TK_PHOTO_PUT_BLOCK;